Texture becomes black when tryng to bake vertex color to texture!
You have no vertex colors, your file has blender render materials but is set to Cycles right now. Turn it back to Blender render. In your scene, you have no light source, so every bake will be black.

edit: My steps were incorrect the first time, so here is a corrected flow:
1. Your file as it is with Cycles as renderer but has no Node materials.

2. I switch to Blender Render and find your UV are wrong, so I Smart UV Unwrap

3.I also then remember in Blender Render that I can bake using Textures to get the straight diffuse color without a lamp

And then the result comes out pretty clean